0
The moment magnitude scale (MW) provides an estimate of the total energy released in an earthquake and is currently the preferred magnitude scale in use by seismologists .
It is calculated from the seismic moment (M0 - which has the unit of dynes/cm =where 1 dyne/cm = 1x10-7 N/m) which is a measure of the total energy released during an earthquake and is derived based on the elastic moduli of the crust where the earthquake occurred, the length of the slip surface and the cross sectional area of the slip surface as follows:
M0 = G x AFx DF
Where:
G = Shear modulus of the rock mass
AF = Area of the rupture along the fault
DF = average displacement on AF
In order to make the moment magnitude scale (Mw) consistent with older magnitude scales such as the Local Moment (or "Richter") scale the seismic moment (M0) is converted into a logarithmic scale using the following equation:
Mw = 2/3 x log10 x (M0) - 10.7
This ultimately yields a dimensionless number and as such, Moment Magnitude has no units.
Please see the related question.
What else can I help you with?
What is the average magnitude of earthquakes worldwide?
The average magnitude of earthquakes worldwide is around 4.5 on the Richter scale.
What are the two locations of the highest magnitude earthquakes and what is the magnitude?
The two locations with the highest magnitude earthquakes are the Valdivia region in Chile with a magnitude of 9.5 in 1960 and the Prince William Sound region in Alaska with a magnitude of 9.2 in 1964.
What percentage of total earthquakes have a magnitude greater than 6.0?
For earthquakes world-wide from 2000 to 2012 there were ~ 2092 quakes with a magnitude 6.0 or higher or less than 1% of the total 332,723 recorded earthquakes according to the USGS National Earthquake Information Center.
What plate boundaries have the largest magnitude earthquakes?
The plate boundaries that have the largest magnitude earthquakes are convergent plates. Convergent plates are moving together and eventually collide. These plates are usually along the edge of an ocean and next to a continent.
What is the name of the scale that measures earthquakes?
The Richter scale was originally developed to measure the strength or magnitude of moderate earthquakes (magnitudes less than 7). The surface wave magnitude scale was then developed by Richter and Guttenburg to allow larger earthquake magnitudes to be measured (up to 8). To measure large earthquakes the moment magnitude scale must be used. To measure the severity of earthquakes, the Modified Mercalli intensity scale is used in the US and the Macroseismic scale is used in Europe.
What units are typically used to measure the magnitude of earthquakes?
Earthquakes are typically measured using the Richter scale or the moment magnitude scale, which are both units of measurement for the magnitude of earthquakes.
What are high magnitude earthquakes?
High magnitude earthquakes are seismic events with a magnitude of 7.0 or greater on the Richter scale. These earthquakes can cause widespread damage to buildings, infrastructure, and the environment, as well as posing significant risks to human life. Proper preparedness and response measures are crucial in mitigating the impact of high magnitude earthquakes.
Why are there fewer magnitude 2 and 3 earthquakes instead of magnitude 4 earthquakes?
There are far more magnitude 2 or 3 earthquakes than magnitude 4 earthquakes. The small quakes just don't get noticed as much because they typically do little or no serious damage.
What is the average magnitude of earthquakes worldwide?
The average magnitude of earthquakes worldwide is around 4.5 on the Richter scale.
What are the standard units used to measure the magnitude of earthquakes?
The standard units used to measure the magnitude of earthquakes are the Richter scale and the moment magnitude scale.
What does magnitude have to do with earthquakes?
The word magnitude (in the context of earthquakes) is used to describe the amount of energy released when one occurs.
How high can an earthquake's magnitude go?
An earthquake's magnitude can go as high as 10 or above on the Richter scale. Magnitude 10 earthquakes are extremely rare and are considered to be the strongest earthquakes ever recorded. The majority of earthquakes are of lower magnitude, with the average being around magnitude 4.
How is an earthquakes energy measured?
Magnitude
Do all earthquakes have after shock?
No only middle and big magnitude earthquakes do.
How is the moment magnitude used to describe earthquakes?
The moment magnitude scale can be used to rate earthquakes of all sizes, near or far.
How many earthquakes over magnitude 8 were recorded in 1981?
This is not a record of a Magnitude 8 or Greater Earthquake during the year
Which is a factor in calculating the moment magnitude of an earthquake?
magnitude of past earthquakes in the area
